Move .ico hashing to icon_util

ui/gfx/icon_util.cc

Index: ui/gfx/icon_util.cc
diff --git a/ui/gfx/icon_util.cc b/ui/gfx/icon_util.cc
index 37ab0d59f53b16e2a702038c541697817ce1ff00..8f7f1ea0c05b3d9dcf244606725d93af167d2e92 100644
--- a/ui/gfx/icon_util.cc
+++ b/ui/gfx/icon_util.cc
@@ -6,6 +6,7 @@
 
 #include "base/file_util.h"
 #include "base/logging.h"
+#include "base/md5.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/win/resource_util.h"
 #include "base/win/scoped_gdi_object.h"
@@ -20,6 +21,9 @@
 
 namespace {
 
+const base::FilePath::CharType kIconChecksumFileExt[] =
+    FILE_PATH_LITERAL(".ico.md5");
+
 struct ScopedICONINFO : ICONINFO {
   ScopedICONINFO() {
     hbmColor = NULL;
@@ -707,3 +711,60 @@ void IconUtil::ComputeBitmapSizeComponents(const SkBitmap& bitmap,
   size_t masks_size = *xor_mask_size + and_mask_size;
   *bytes_in_resource = masks_size + sizeof(BITMAPINFOHEADER);
 }
+
+void IconUtil::GetImageCheckSum(const gfx::ImageFamily& image,
+                                base::MD5Digest* digest) {
+  DCHECK(digest);
+  base::MD5Context md5_context;
+  base::MD5Init(&md5_context);
+
+  for (gfx::ImageFamily::const_iterator it = image.begin(); it != image.end();
+       ++it) {
+    SkBitmap bitmap = it->AsBitmap();
+
+    SkAutoLockPixels image_lock(bitmap);
+    base::StringPiece image_data(
+        reinterpret_cast<const char*>(bitmap.getPixels()), bitmap.getSize());
+    base::MD5Update(&md5_context, image_data);
+  }
+
+  base::MD5Final(digest, &md5_context);
+}
+
+bool IconUtil::SaveIconWithCheckSum(const base::FilePath& icon_file,
+                                    const gfx::ImageFamily& image) {
+  if (!CreateIconFileFromImageFamily(image, icon_file))
+    return false;
+
+  base::MD5Digest digest;
+  GetImageCheckSum(image, &digest);
+
+  base::FilePath cheksum_file(icon_file.ReplaceExtension(kIconChecksumFileExt));

[Alexei Svitkine (slow), 2013/05/09 15:34:57]

Nit: cheksum -> checksum

+  return file_util::WriteFile(cheksum_file,
+                              reinterpret_cast<const char*>(&digest),
+                              sizeof(digest)) == sizeof(digest);
+}
+
+bool IconUtil::ShouldUpdateIcon(const base::FilePath& icon_file,
+                      const gfx::ImageFamily& image) {

[Alexei Svitkine (slow), 2013/05/09 15:34:57]

Nit: Align.

+  base::FilePath checksum_file(
+      icon_file.ReplaceExtension(kIconChecksumFileExt));
+
+  // Returns true if icon_file or checksum file is missing.
+  if (!file_util::PathExists(icon_file) ||
+      !file_util::PathExists(checksum_file))
+    return true;
+
+  base::MD5Digest persisted_image_checksum;
+  if (sizeof(persisted_image_checksum) != file_util::ReadFile(checksum_file,
+                      reinterpret_cast<char*>(&persisted_image_checksum),
+                      sizeof(persisted_image_checksum)))
+    return true;
+
+  base::MD5Digest downloaded_image_checksum;
+  GetImageCheckSum(image, &downloaded_image_checksum);
+
+  // Update icon if checksums are not equal.
+  return memcmp(&persisted_image_checksum, &downloaded_image_checksum,
+                sizeof(base::MD5Digest)) != 0;
+}